The problem: when I try to do an update using an EntityDataSource and a FormView that has an <asp:DropDownList> linking to another table, the page loads fine with the proper setting, but on update I get this error message:

A property named 'Vendor.VendorId' was not found on the entity during an insert, update, or delete operation. Check to ensure that properties specified as binding expressions are available to the data source.

As I said above, the initial page displays just fine; the DropDownList has the right entries in it and the correct vendor is set to the correct value. Just clicking on the Update button causes the above error.

1 Answer
1

Shouldn't the selectedvalue though be from the PartEntityDataSource perspective, because the VendorEntityDataSource isn't binding the overall data bound control, you need to use <%# Bind("VendorID") %> instead.